Smoke eliminator and fuel economizer



Patented Feb. 18, 1 930 UNITED STATES PATENT OFFICE ALFRED E. STUCK ERT, OF LOUISVILLE, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AMERICAN FUEL ECONOMIZER CORPORATION, OF CANTON, OHIO, A CORPORATION OF OHIO SMOKE ELIMINATOR AND FUEL ECONOMIZER Application filed January 14, 1928.

My invention relates to combustion appliances for increasing the efficiency of furnaces and the like, and more particularly to smoke eliminators and fuel economizersof the induced air type including one or more ducts in a wall of the furnace firebox, the inlet of eachduct communicating with an air supply, and the outlet of each duct communicating with the firebox, whereby the heated material of the walls in which the ducts are located will induce heated air to flow into the firebox for effecting more complete combustion of the fuel therein, thereby eliminating smoke andeconomizing fuel.

The objects of the present improvements include the provision of a more efficient smoke eliminator and fuel economizer of the induced air type by providing an increased area of heated duct surface for contacting with the unit volumes of air induced to flow through each duct, and by providing a duct which will induce a flow of turbulent heated air into the furnace firebox.

These and ancillary objects are attained in the improved smoke eliminator and fuel economizer hereinafter set forth in detail,

and which may be stated in general terms as including a back wall'for the furnace firebox, and one or more tortuous ducts in the back wall, each of whose inlets communicates with the furnace ash pit, and each of whose outlets communicates with the firebox, the duct preferably having a crescent shape cross section'and describing a twisting helical path for-"providing maximum duct surface per unit volume of air passing therethrough, and each duct outlet preferably including one or more spirally curved'passages tapered toward their outer ends for introducing a turbulent jet of airinto the firebox.

' A preferred embodiment of the invention is illustrated in the accompanying drawing I mizer;

forming part hereof, in which Figure 1 is alongitudinal sectional view of a. boiler furnace provided with theimproved smoke eliminator and fuel econo- Fig. 2, an enlarged fragmentary front elevation of a portion of the improved smoke eliminator and fuel economizer;

Serial No. 246,708.

Fig. 3, a detached enlarged view with portions in section illustrating the preferred con struction of the back wall and ducts by means of perforated refractory blocks;

Fig. 4, a fragmentary sectional View illustrating a modified cross section for the tortuous duct; and

F ig. 5, a fragmentary sectional View of anolther modified cross section for the tortuous c not.

Similar numerals refer to similar parts throughout the several views.

A low pressure boiler indicated generally at and a furnace setting indicated at 11 tllGlL'IfOI in Fig. 1 may be of any usual construttion, and may include a firebox 12, grate bars 13, and an ash pit 14, below the firebox and separated therefrom bythe grate bars.

A suitable firing door 15, and a suitable ash pit door 16 provide access through suitable apertures in the front wall 17 of the boiler setting tov the firebox 12 and the ash pit 14 respectively.

The firebox communicates at its rear end as by a duct 18 with the boiler in a usual manner, and the firebox back wall 19 may extend upwardly to form a back wall for the duct/18.

The improved smoke eliminator and fuel economizer of the present invention is formed preferably by the use of specially shaped refractory blocks 20, 21, and 22 supported by the grate bars and arranged in front of the back wall 19 of the firebox.

The blocks 20 and 21 are preferably of the same width and each block 21 rests upon the top of ablock 20, there being preferably a tongue and groove connection indicated at 23 between the abutting faces of the blocks 20 and 21.

It is preferred to provide a series of the blocks 20 and 21 to extend across the full width of the firebox, and tongue and groove connections indicated at 24 are provided between the side by side abutting faces of the blocks. 4

Each block 21is preferably provided with an overhangingforward projection 25 for protecting the exit apertures from being filled up with soot, dirt and the like.

The blocks 21 are preferably of less depth or the like. with duct sections, which register with each other when the blocks are'pro'perly arranged for use, to provide a tortuous duct whose inlet 27 communicates with the ash pit 14 for drawing air therefrom, and whose outlet passages 28 communicate with the firebox 12 for forwardly directing turbulent jets of heated air into the firebox.

It is preferred that the duct section 29 in each block 20 shall have a crescent shape cross section 29 and describe an axially vertical helical path from the inlet 27 to the juncture at 30 of the duct section 29 with the duct section 31 in a block 21. Moreover, the axis of the spiral duct 29 is offset from the longitudinal axis of each block 20.

The duct section 31 in each block 21 describes a twisting path forwardly to a fork chamber 32 adjacent the front face of the block, and from the fork chamber 32 a plurality of spirallycurved passages tapered to- Ward their outer ends 33 connect with a plurality of similarly shaped passages 34 in an abutting nozzle block 22.

By this construction of the blocks with duct sections therein forming a tortuous duct communicating from the ash pit'to the firebox; when the blocks are heated by the burning fuel in the firebox, heated air will be induced to flow through the tortuous duct and to be introduced as turbulent jets into the firebox through the orifices 34.

The provision of the crescent cross-section for the duct and the twisting helical path provides maximum heated duct surface area per unit volume of air passing therethrough.

The introduction of the heatedair into the firebox in a swirling motion which will insure thorough co-mingling of the oxygen with the combustible gases aids combustion therein by adding to the fire the necessary oxygen in a heated state, thereby eliminating all CO gases and thus efi'ecting a C0 offourteen or fifteen and producing what is known as complete combustion.

The modified crescent cross section 2.9 for the duct illustrated in Fig. 4 includes longitudinally extending grooves 35 which provide a greater area of duct surface; and the modified crescent cross section 29' illus trated in Fig. 5 is provided with a single upper groove 36. for admitting a relatively large quantity of air.

By thus providing sufiicient heated oxygen for combustion, the flame 1s carrled away from the grate bars, toward the economizer,

thus relieving the grate bars from excess punishment by the fire.

Although for the purpose of illustration this device is shown in connection with a low pressure boiler, it should be understood that it is applicable to any kind of furnace, boiler, locomotive or kiln and may be used with any kind of coal, coke or oil.

I claim:

1. A combustion appliance for inducing a fiow of air into a furnace firebox, including walls adapted to be heated by the fuel burning in the firebox, and forming a spiral duct having an inlet communicating with an air supply and an outlet communicating with the firebox, the duct having a crescent cross-section.

2. A combustion appliance for inducing a fiow of air into a furnace firebox, including a plurality of blocks ada ted to be heated by the fuel burning in the rebox, each'of said blockshaving a spiral duct provided with an inlet communicating with an air supply and an outlet communicating with the firebox and interfitting vertical and horizontal tongues and grooves upon said blocks for preventing air from rising between the blocks.

3. A combustion appliance for inducing a flow of air into a furnace firebox, including walls adapted to be heated by the fuel burning in the firebox, and forming a spiral duct having an inlet communicating with an air supplyand an outlet communicating with the firebox, the duct beingcrescent sh ped and corrugated in' cross-section to, produce the maximum heating surface forthe air.

4. A combustion appliance for inducinga flow of air into a furnace fire box, including walls adapted to. be heated by the fuel burning in the fire box, and forming a spiral. duct having an inlet communicating with an air supply and an outlet passage communicating with the fire box, the outlet passage being spirally curved and tapered toward its outer end.

5. A combustion appliance for inducing a flow of air into a furnace fire box, including walls adapted to, be heated by the fuel burning in the fire box, and forming a spiral duct having an inlet communicating with an air supply and an outlet passage communicating with the fire box, the duct having a crescent cross-section, and the outlet passage being spirally curved and tapered toward its outer end. i

6. A combustion appliance for inducing a flow of air. into a furnace fire b0X, inclucling two blocks adapted to be heated by the fuel burning in the. fire box, one of the blocks forming; a spiral duct having an inlet communicating with an, air supply, and, the other block forming an outlet communicating with the fire box and With Said spiral; duct, said outlet being soconstructed as to cause the ir to swirl as it leaves the same.

7. A combustion appliance for inducing a flow of air into a furnace fire box, including two blocks adapted to be heated by the fuel burning in the fire box, oneof the blocks forming a spiral duct having an inlet communicating with an air supply, and the other block forming an outlet communicating With the fire box and with said spiral duct, the longitudinal axis of the spiral being offset from the longitudinal axis of the block forming the spiral duct.

In testimony that I claim the above, I have hereunto subscribed my name.

ALFRED E. STUGKERT. 

